Doesn't GameStop repair these?
Did you even watch the video yet ?
The HDMI port is 4 pins, then some smaller pins to solder. Using "Flux" (a paste you put on the pins) makes the solder only stick to metal so its basically touch one, move to the other... touch one, move to another pin. (As seen in the video) It is really easy to do, you just need a steady hand and the part and flux and solder.. using a soldering iron.
I gave you a 'teardown' video to watch to open the ps4 as well.
If this port was just "fixed before" as you said, then bend the 4 pins once it sticks through the motherboard.. that holds the HDMI port in place on the board.
As mentioned in the video, these ports are not that great they tend to malfunction.. so those 4 pins I personally would bend over slightly as it sticks through the board.. before soldering.
Then work on the smaller pins.
You can watch Louis Rossmann on youtube fix macbooks to get an idea how to solder.
Honestly, for about $20 you can do this yourself (price of flux, solder, and HDMI port).. even a soldering iron from a friend. Just sand the tip down to a thin point before pluggin in the soldering iron. IF you mess up the solder job, just buy 'solder wick' and put it onto the part you messed up then hold the soldering tip on top of the wic, it will suck up the solder you messed up on.. It honestly is not hard to do. Most of the time people are just scared to do it.
Be a man!